<!DOCTYPE html>
<html>

	<head>
		<meta charset="utf-8">
		<title></title>
		<script src="js/jquery-1.11.0.js" type="text/javascript" charset="utf-8"></script>
	</head>
	<style type="text/css">
		.dashed-box{width:500px;height:100px;overflow:hidden;position:relative;}
.dashed-top{width:2000px;height:0px;border-bottom:2px #ccc dashed;position:absolute;top:0;left:-1400px;}
.dashed-left{width:0px;height:2000px;border-left:2px #ccc dashed;position:absolute;left:0;top:-1600px;}
.dashed-bottom{width:2000px;height:0px;border-bottom:2px #ccc dashed;position:absolute;left:0px;bottom:0;}
.dashed-right{width:0px;height:2000px;border-left:2px #ccc dashed;position:absolute;right:0;top:-1600px;}
	</style>

	<body>
		<div class="dashed-box">
			<div class="dashed-top"></div>
			<div class="dashed-left"></div>
			<div class="dashed-right"></div>
			<div class="dashed-bottom"></div>
		</div>

		<script type="text/javascript">
			setInterval(function(){
		 var $left=$(".dashed-top").css("left");
		 var $top=$(".dashed-bottom").css("left");
		 $left=parseInt($left);
		 $top=parseInt($top);
		 if($left<0){
		  $left+=2;
		 }else{
		  $left=-1400;
		 }
		   
		 if($top>-1000){
		  $top-=2;
		 }else{
		  $top=0;
		 }
		 $(".dashed-top").css("left",$left+"px");
		 $(".dashed-right").css("top",$left+"px");
		 $(".dashed-bottom").css("left",$top+"px");
		 $(".dashed-left").css("top",$top+"px");
		},60);
		</script>
	</body>

</html>